The Klingon Empire's capital world, also spelled Kronos.
Qo'noS is the homeworld of the Klingon Empire, a harsh and rugged planet with wide, rocky landscapes and a large moon, Praxis. Its capital is the First City, where the High Council meets, and its fortress cities and old temples reflect the warlike and proud history of its people.
In the twenty-third century, the explosion of Praxis, the moon that supplied much of the planet's energy, devastated the Klingon economy and the planet's environment. This disaster forced the empire to seek peace with the Federation, which led to a historic change in relations between the two powers. The planet became a place where Klingon honour and politics were played out.
Qo'noS appears in many episodes and films, including Star Trek VI: The Undiscovered Country, in which Kirk and McCoy are put on trial for the murder of Chancellor Gorkon. Captain Picard also visits it in the Next Generation, including in Sins of the Father and Redemption, and Worf's family and political fortunes revolve around the planet.